Simplify the following expression: $y = \dfrac{k^2 - 17k + 70}{k - 10} $
Answer: First factor the polynomial in the numerator. $ k^2 - 17k + 70 = (k - 10)(k - 7) $ So we can rewrite the expression as: $y = \dfrac{(k - 10)(k - 7)}{k - 10} $ We can divide the numerator and denominator by $(k - 10)$ on condition that $k \neq 10$ Therefore $y = k - 7; k \neq 10$